Deciphering the ECG allows you to reliably identify abnormalities in cardiac activity by examining the curve with the image of the heart rhythm. An electrocardiogram is a study of cardiac activity over a certain period of time. It reflects the electrical processes in the heart muscle, such as depolarization - excitation, and repolarization - restoration of myocardial cells. An electrocardiogram is performed transthoracically, that is, through the chest, using electrodes installed on the surface of the skin, with further recording of the readings on a special device. Correct interpretation of the ECG provides an opportunity to visually establish an accurate diagnosis and, if necessary, determine a timely course of treatment.
ECG consists of images of teeth, segments and intervals. The teeth of the cardiogram are the extreme points of the curved line, which are indicated by Latin letters characterizing the following indications: atrial contraction (P), ventricular contraction (Q, R, S) and relaxation of the ventricles (T). The "U" wave is intermittent and rarely recorded. Segments are straight line segments connecting adjacent teeth. Mostimportant is the interpretation of the ECG in the P-Q and S-T segments. For example, the P-Q isoline is formed during the period of excitation delay in the atrioventricular (atrioventricular) node. Intervals are a combination of teeth and segments. The most important ECG intervals are the P-Q and Q-T intervals.
Excitation in the myocardium of the cardiac ventricles is characterized by the appearance of a complex QRS complex on the ECG, since it is not only more massive than the atrial muscle, but also has an interventricular septum. In the QRS complex, the dimensions of individual teeth are first assessed. If the amplitude of the tooth exceeds 5 millimeters, it is designated with a large Latin letter Q, R, and S, when the amplitude of its movement has a smaller range, it is written with a small letter q, r or s. Deciphering the ECG implies the correct reading of the teeth. The R (r) wave is each upward-positive wave included in the QRS complex. Any downward - negative prong located before the R wave is written as Q (q), and located after the R wave is the S (s) wave. The Q wave characterizes the depolarization of the interventricular septum; in myocardial infarction, it has an expanded and in-depth value. The R wave shows the depolarization of the main mass of the myocardium, and the S wave shows the activity of the atrial sections of the interventricular septum.
Deciphering the ECG of the heart consists of five points of the study of indications:
1. Analysis of heart rate and cardiac conduction. This analysis meansassessment of the periodicity of heart contractions, determination of the heart rate (HR), the establishment of an excitatory source and a characteristic of conduction;
2. Determining the axis of electrical impulses of the heart;
3. Atrial P wave examination;
4. Exploring the QRST complex;
5. Conclusion of ECG diagnostics.
Deciphering the electrocardiogram of a he althy human heart begins with a short atrial wave (a-b), reflecting the change in ventricular capacity when blood enters at the time of systole - atrial contraction. In the ECG, this wave is located behind the P wave and then goes up, showing ventricular systole. This steep rise (b-d) follows the Q wave and turns into a horizontal position (d-e). During the period of relaxation of the left ventricle and a decrease in pressure in it, the curve drops sharply down (e-g), the g point corresponds to the opening of the mitral valve and the flow of blood into the ventricles. On the contraction wave there is point c, which corresponds to the stressed state of the mitral valve, and point f, corresponding to the closing of the aortic valve. Following the systolic wave, a wave of filling of the ventricles (g-h) and their slow filling (k-a) is formed. This is followed by a repeat of the ECG cycle of a he althy human heart.
